Hyperfocal Distance

http://www.dofmaster.com/hyperfocal.html

เอาข้อมูลที่อ่านมา กับที่มีคนเอามาฝากมาแปะรวมกันตรงนี้ค่ะ (ขอบคุณNapnik สำหรับข้อมูลเพิ่มเติมค่ะ)

-------------------------------------------

From the link above: HFD from dofmaster.com

"The concept of hyperfocal distance is easy to understand: focus a lens at the hyperfocal distance and everything in the photograph from some near distance to infinity will be sharp. Landscape photographs are often taken with the lens focused at the hyperfocal distance; near and distant objects are sharp in the photos.

Application of the concept leads to many questions: Which lenses are best for using hyperfocal distance focusing? What is the hyperfocal distance for a lens? How do I focus at the hyperfocal distance? Do I have to focus exactly at the hyperfocal distance? In this article we'll look at the basics of using hyperfocal distance to maximize depth of field in a photograph... Read more

-------------------------------------------


Where to focus (Hyper Focal Distance)

เรื่องการหาจุดโฟกัสในการถ่ายภาพแบบแลนด์สเคปนี้มีปัญหามานานและยังมีบ้างต่อไป แต่น้อยลง (ขอบคุณคุณJoe Panch ที่เคยแนะนำเรื่องนี้ไว้) หาที่เขียนดีๆ ให้เข้าใจได้ง่ายมานานเพิ่งเจอค่ะ เลยเอามาแปะเผื่อมีคนมีปัญหาเดียวกันจะสนใจ

by Jeff Revell, Canon 50D, From Snapshots to Great Shots, Peachpit Press, 2009, pp-182-183

"Large landscape scenes are great fun to photograph, but they can present a problem: where exactly do you focus when you want everything to be sharp? Since our goal is to create a great landscape photo, we will need to concentrate on how to best create and image that is tack sharp, with a depth of field that renders great focus throughout the scene.

I have already stressed the importance of good tripod when shooting landscapes. The tripod lets you concentrate on the aperture portion of the exposure without worrying how long your shutter will be open. This is because the tripod provides the stability to handle any shutter speed you might need when shooting at small apertures. I find that for most of my landscape work I set my camera to Aperture Priority mode and the ISO to 100 (for a clean, noise-free image).

However, shooting with the smallest aperture on your lens doesn't necessarily mean that you will get the proper sharpness throughout your image. The real key is knowing where in the scene to focus our lens to maximize the depth of field for our chosen aperture. To do this, you must utilize something called the "hyper focal distance" of your lens.

Hyper focal distance, also referred to as HFD, is the point of focus that will give you the greatest acceptable sharpness from a point near your camera all the way out to infinity. If you combine good HFD practice in combination with a small aperture, you will get images that are sharp to infinity.

There are a couple of ways to do this, and the one that is probably the easiest, as you might guess, is the one that is most widely used by working pros. When you have your shot all set up and composed, focus on an object that is about one-third of the distance into your frame. It is usually pretty close to the proper distance and will render favorable results. When you have the focus set, use your Depth of Field preview button to check the sharpness of all the objects in your scene. The button is located just under the lens release button and is activated once you have depressed the the shutter button partway."

-------------------------------------------

อันนี้เป็นลิงก์สำหรับคนชอบคำนวณ

* :: Focus Pocus :: Depth of Field Calculators for Photographers

-------------------------------------------

อันนี้ลิงก์ต้นกระทู้จาก pantip.com ค่ะ แต่บางทีคลิ้กแล้วหาหน้าไม่เจอจากทางนี้ แปะไว้ก่อน เผื่อกลับมาแล้วเข้าได้

http://topicstock.pantip.com/camera/topicstock/O3001253/O3001253.html